1. Field of the Invention
The present invention relates to an oil separator for separating lubricating oil from a gaseous refrigerating medium used in a refrigerating system such as air conditioner for an automobile.
2. Description of the Related Arts
In a refrigerating cycle, a refrigerating medium is compressed in a compressor, delivered to a condenser to be condensed and cooled therein, fed to an evaporator via an expansion valve for a heat exchange, and then returned from the evaporator to the compressor.
In such a conventional refrigerating cycle, lubricating oil is mixed in the refrigerating medium for lubricating the compressor, and thus the refrigerating medium output from the compressor contains lubricating oil therein. This lubricating oil contained in refrigerating medium, however, has far different condensation and evaporation properties from those of the refrigerating medium, and if such a lubricating oil is fed to the condenser and the evaporator, the heat exchange performance, and thus the performance of the refrigerating cycle, is lowered.
Accordingly, conventionally an oil separator is arranged between the outlet of the compressor and the inlet of the condenser, for separating the lubricating oil from refrigerating medium output from the compressor and returning the separated lubricating oil to the suction side of the compressor.
Typical of these centrifugal type oil separators are those proposed and disclosed in, for example, Japanese Unexamined Utility Model (Kokai) No. 55-102913, No. 55-104785, No. 56-88071, and 64-1721.
Currently, a variable capacity type compressor is widely utilized in an air conditioner for an automobile, and a new refrigerating medium is used due to the restrictions on the use of flon. Accordingly, the return of the lubricating oil to the compressor has become less satisfactory, and thus the demand for an efficient oil separator has increased.
Nevertheless, a conventional oil separator, such as that described in the above cited references, comprises a unit separated from the other unit, i.e., the compressor, and thus a problem arises in that the structure of the refrigerating system has become more complicated.